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Port 2128 (net-steward)

IANA assigns port 2128 to net-steward: Net Steward Control.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
net-steward TCP Net Steward Control Martin Norman -
net-steward UDP Net Steward Control Martin Norman -

Check what is listening on port 2128

Linux: is anything listening on TCP 2128?
sudo ss -tlnp 'sport = :2128'
Linux: UDP 2128
sudo ss -ulnp 'sport = :2128'
Linux / macOS: which process owns the port
sudo lsof -nP -i :2128
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':2128 '
Windows (Command Prompt)
netstat -ano | findstr :2128
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2128 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 2128
From Windows
Test-NetConnection HOST -Port 2128
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 2128

Block port 2128 in the firewall

ufw
sudo ufw deny 2128/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 2128 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 2128 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 2128' -Direction Inbound -Protocol TCP -LocalPort 2128 -Action Block
ufw
sudo ufw deny 2128/udp
iptables
sudo iptables -A INPUT -p udp --dport 2128 -j DROP
nftables
sudo nft add rule inet filter input udp dport 2128 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 2128' -Direction Inbound -Protocol UDP -LocalPort 2128 -Action Block

Related ports

2126pktcable-cops2127index-pc-wb2129cs-live2130xds

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.